Stretching vibrations of the V(O2) group and structure of vanadium(V) peroxo complexes

1983 ◽  
Vol 48 (1) ◽  
pp. 248-253 ◽  
Author(s):  
Peter Schwendt
Keyword(s):  
Coordination Polyhedron ◽  
Infrared Spectra ◽  
Published Data ◽  
Peroxo Complexes ◽  
Composition And Structure ◽  
Different Types ◽  
Stretching Vibrations ◽  
Spectral Patterns

The infrared spectra of some vanadium(V) peroxo complexes were measured and supplemented with published data ( a total of 33 complexes) to seek for relations between the stretching vibrations of the V(O2) group and the structure of the complexes. While no such relation could be established in the region of 9.10 - 800 cm-1, in the 660 - 490 cm-1 range the spectral patterns were found sensitive to the composition and structure of the coordination polyhedron, thus making it possible to discriminate between complexes of different types.

Preparation of 3-cyano-4-(R-vinyl)-5,5-dimethyl-Δ3-butenolides and substituent effects on their infrared spectra

1989 ◽  
Vol 54 (6) ◽  
pp. 1666-1674 ◽  
Author(s):  
Alexander Perjéssy ◽  
Aida Avetisovna Avetisyan ◽  
Anna Alexandrovna Aknazaryan ◽  
Gagik Surenovich Melikyan
Keyword(s):  
Infrared Spectra ◽  
Substituent Effects ◽  
Aromatic Aldehydes ◽  
The Other ◽  
Wave Numbers ◽  
Different Types ◽  
Group A ◽  
Stretching Vibrations ◽  
Transmission Factors ◽  
Statistical Results

Twenty nine 3-cyano-4-(R-vinyl)-5,5-dimethyl-Δ3-butenolides were prepared by condensation of 3-cyano-4,5,5-trimethyl-Δ3-butenolide with aliphatic and aromatic aldehydes. The wave numbers of C=O, C=N and C=C stretching vibrations of synthesized compounds were measured in trichloro- and tetrachloromethane. The spectral data were correlated with substituent conotants using Hammett-Brown and the improved and extended Seth-Paul-Van Duyse equation. The statistical results of correlations were compared with those of ethyl α-cyanocinnamates, ethyl benzoates and benzonitriles. The transmission factors for one and two C=C bonds were determined in the regions of π' = 0.46-0.57 and 0.27-0.37, respectively. In 3-cyano-4-(arylvinyl)-5,5-dimethyl-Δ3-butenolides a considerable conjugation exists between the arylvinyl moiety and both the C=O and C=N groups. On the other hand, in 3-cyano-4-(alkylvinyl)-5,5-dimethyl-Δ3-butenolides probably only the endocyclic C=C bond takes part in a marked resonance interaction with alkylvinyl group. A generally valid relationship was found between the slopes of ν(C=O) vs σ+ and ν(C=N) vs σ+ correlations for different types of compounds measured in CHCl3 and CCl4.

Numerical Simulations of Dynamic Embedment During Pipe Laying on Soft Clay

2009 ◽  
Author(s):  
D. Wang ◽  
D. J. White ◽  
M. F. Randolph
Keyword(s):  
Soft Clay ◽  
Simple Approach ◽  
Published Data ◽  
Vertical Load ◽  
Centrifuge Model ◽  
Upper Limit ◽  
Different Types ◽  
Element Approach ◽  
Pipeline Design ◽  
Centrifuge Model Tests

Prediction of the as-laid embedment of a pipeline, which affects many aspects of pipeline design, is complicated by the dynamic motions that occur during the lay process. These motions cause pipelines to embed deeper than predicted based on static penetration models, as the seabed soils are both softened and physically displaced by the pipeline motion. This paper describes the results of 2D numerical analyses using a large displacement finite element approach aimed at quantifying pipeline embedment due to cyclic lateral motion at various fixed vertical load levels. The validity of the numerical results is first assessed by comparison with published data from centrifuge model tests in two different types of clay. A parametric study varying the normalized vertical load is then presented, which suggests a simple approach for estimating an upper limit to the dynamic embedment.

The effect of high temperature on kernel dimensions and the type and occurrence of kernel damage in rice

1991 ◽  
Vol 42 (3) ◽  
pp. 485 ◽  
Author(s):  
T Tashiro ◽  
IF Wardlaw
Keyword(s):  
High Temperature ◽  
Oryza Sativa L ◽  
Temperature Treatment ◽  
High Temperature Treatment ◽  
Published Data ◽  
Starch Granules ◽  
Endosperm Tissue ◽  
Razor Blade ◽  
Light Refraction ◽  
Different Types

Rice (Oryza sativa L. cv. Calrose) growing at 27/22�C was either transferred to day/night temperatures ranging from 24/19 to 39/34�C 7days after heading and held at these temperatures until maturity, or transferred to a temperature of 36/31�C for 8 day periods at regular intervals commencing from heading. Kernel dimensions were measured directly and the types of kernel damage at maturity were characterized by direct viewing under the light microscope of intact and sectioned kernels, or by scanning electron microscopy of the exposed surface of kernels cut transversely with a razor blade. Kernel thickness was reduced most by high temperature treatments commencing 12 days after heading, but other kernel dimensions (length and width) were most sensitive to high temperature earlier in development. Sterility and pathenocarpy were most evident when temperature treatments commenced at heading (approximately 2 days before anthesis) and were greatest at the highest temperature (39/34�C). Abortive and opaque kernels were most evident when the high temperature commenced 4 days after heading and were also most numerous at the highest temperature tested. From observations on the morphology of the kernels it appears that temperatures above 27/22�C can interfere with the early stages of cell division and development in the endosperm. Chalky endosperm tissue occurred in several forms depending on both the temperature level and the timing of the temperature treatment. White-core kernels were only evident at a temperature of 27/22�C. White-back kernels were most numerous at 36/31�C and when the high temperature treatment commenced 16 days after heading. Milky-white kernels were found in all but the lowest temperature treatment (24/19�C), with a peak at 36/31�C and this type of damage was most evident when the high temperature treatment commenced 12 days after heading. Differences in endosperm cellular morphology were observed between the different types of damage, and in accord with other published data the chalky appearance was associated with the development of numerous air spaces between loosely packed starch granules and a change in light refraction.

Synthesis, spectral and electrochemical study of coordination molecules Cu4OX6L4: 4-cyanopyridine Cu4OBrnCl(6−n)(4-CNpy)4 complexes

2010 ◽  
Vol 64 (3) ◽  
Author(s):  
Gregor Ondrejovič ◽  
Adela Kotočová ◽  
Marian Koman ◽  
Peter Segľa
Keyword(s):  
Cyclic Voltammetry ◽  
Infrared Spectra ◽  
Electronic Spectra ◽  
Pyridine Ring ◽  
Pyridine Complexes ◽  
Half Wave ◽  
Out Of Plane ◽  
Donor Acceptor ◽  
Back Bonding ◽  
Stretching Vibrations

AbstractNew 4-cyanopyridine halide and mixed-halide Cu4OBrnCl(6−n)(4-CNpy)4 complexes (4-CNpy = 4-cyanopyridine, n = 0–6) were synthesised, characterised, and studied by infrared spectra, electronic spectra, and cyclic voltammetry. Infrared spectra revealed donor-acceptor vibrational couplings of the Cu4O, Cu-Cl, and Cu-N stretching vibrations with the in-plane and out-of-plane pyridine ring vibrations. The infrared spectra, electronic spectra, and half-wave potentials correspond to a weak donor and a strong acceptor behaviour of the 4-cyanopyridine ligands and to π-back bonding, Cu(II)→pyridine rings. The results were compared with the related pyridine and 4-substituted pyridine complexes.

Imogolite: a unique aluminosilicate

Clay Minerals ◽  
1969 ◽  
Vol 8 (1) ◽  
pp. 87-99 ◽  
Author(s):  
J. D. Russell ◽  
W. J. McHardy ◽  
A. R. Fraser
Keyword(s):  
Electron Diffraction ◽  
Infrared Absorption ◽  
Chain Structure ◽  
Absorption Bands ◽  
Repeat Units ◽  
Sample Orientation ◽  
Different Types ◽  
Stretching Vibrations ◽  
Diffraction Patterns ◽  
Silicate Chain

The fibrous aluminosilicate imogolite has been studied by electronoptical and infrared absorption methods. Electron diffraction patterns are interpreted in terms of repeat units of 8·4 Å parallel and 23 Å perpendicular to the fibre axis. These spacings can not be reconciled with a continuous silicate chain structure and this conclusion is supported by an Si-O vibration near 930 cm−1. A structure is postulated in which distorted chains of Al-O octahedra are cross-linked through isolated Si2O7 groups.Multiple OH stretching vibrations indicate different types of OH group in the imogolite structure. Absorption bands near 1000, 700 and 600 cm−1 are sensitive to sample orientation. This is attributed to the morphology and dimensions of the imogolite fibres.

scholarly journals Laboratory Spectra of Amorphous and Crystalline Olivine: An Application to Comet Halley IR Spectrum

1991 ◽  
Vol 126 ◽  
pp. 125-128 ◽  
Author(s):  
A. Blanco ◽  
V. Orofino ◽  
E. Bussoletti ◽  
S. Fonti ◽  
L. Colangeli ◽  
...  
Keyword(s):  
Experimental Data ◽  
Infrared Spectra ◽  
Ir Spectrum ◽  
Emission Feature ◽  
Cosmic Dust ◽  
Dust Grains ◽  
Natural Mineral ◽  
The Third ◽  
Different Types ◽  
Comet Halley

AbstractAmong the various silicates proposed as components of cosmic dust grains, olivine is considered one of the most likely materials. In this work we present the infrared spectra of three different types of olivine grains: crystalline, amorphous and synthetic (also amorphous). While the first and second sample derive from the same natural mineral, the third one has been prepared in the laboratory according to the relative cosmic abundances of the elements. The experimental data are used to fit the emission feature observed in the comet Halley spectrum between 8 and 13μm.Satisfactory results are obtained by using synthetic olivine mixed with a small amount (5%) of crystalline grains.

The infrared spectra of theobromine salts

1967 ◽  
Vol 45 (23) ◽  
pp. 2899-2902 ◽  
Author(s):  
Denys Cook ◽  
Zephyr R. Regnier
Keyword(s):  
Hydrogen Bond ◽  
Nitrogen Atom ◽  
Infrared Spectra ◽  
Imidazole Ring ◽  
Free Base ◽  
Absorption Bands ◽  
Out Of Plane ◽  
Stretching Vibrations ◽  
Deformation Modes ◽  
Infrared Absorption Bands

From the infrared spectra of theobromine salts it is concluded that the salts are probably arranged in hydrogen-bonded centrosymmetric pairs involving [Formula: see text] interactions. [Formula: see text] anion− hydrogen bonds are formed by protonation of the free nitrogen atom (N9) in the imidazole ring. Infrared absorption bands arising from the former hydrogen bond constantly appear near 3 000 cm−1, whereas those from the latter shift from 2 580 to 3 300 cm−1, depending on the anion. In-plane NH and N+H deformation modes give bands near 1 485 and 1 160 cm−1, respectively. Out-of-plane NH modes have been located, but precise assignments are not possible.The assignments for some other bands which show deuteration shifts are detailed, and the carbonyl stretching vibrations which increase in frequency on protonation of the free base are identified.

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